The present invention relates generally to machinery and methods for servicing wheels and more particularly to wheel servicing machines having a pivotable swing arm for assisting in tire mounting or demounting operations.
Wheel servicing machines having a pivotable swing arm are known in the art. Such wheel servicing machines can include tire changing machines useful for assisting in the mounting and demounting of automobile tires on a wheel rim. Some conventional wheel servicing machines can include a swing arm pivotally attached to a support tower. The swing arm is angularly moveable relative to a machine base positioned below the swing arm. A tool head is positioned on the end of the swing arm. The tool head can be mounted on a moveable arm shaft and vertically adjusted for accommodating different sized wheels and tires. During use, the tool head must be angularly and vertically positioned relative to the wheel rim at a precise location for properly performing the wheel servicing operations.
Precise angular positioning of the tool head relative to the wheel rim is achieved in conventional wheel servicing machines by manually moving the swing arm relative to the wheel rim. The swing arm can be pivoted toward the wheel rim so that the tool head approaches and engages the wheel rim at the desired location. The wheel rim can then be rotated on the base while the tool head engages the wheel rim or tire. Following rotation of the wheel rim and desired engagement of the wheel rim or tire by the tool head, the swing arm can then be angularly moved away from the wheel rim by manually pushing the swing arm to the side using the operator's hand.
Some conventional wheel servicing machines include a flange protruding from the support tower near the swing arm. The flange includes a threaded flange passage and a threaded bolt extending through the flange passage having a distal bolt end protruding toward the swing arm. The opposite end of the threaded bolt includes a knob or handle for manually screwing or unscrewing the threaded bolt through the flange passage, thereby adjusting the axial position of the threaded bolt in the threaded flange passage. By turning the knob, the distal bolt end can be moved toward or away from the swing arm. The distal bolt end provides an angular stop position for the swing arm. When the swing arm is moved toward the wheel rim, the swing arm engages the threaded bolt and stops at the desired angular stop position defined by the bolt.
One problem associated with conventional threaded-bolt swing arm angular positioning assemblies occurs when wheel rims having different rim diameters are sequentially serviced using the same wheel servicing machine. For example, when a first wheel rim having a first rim diameter is positioned on the wheel servicing machine, the knob can be used to define an angular stop position associated with the first wheel diameter. Using the conventional configuration, the operator must use one hand to manually position the swing arm at the desired angular stop position and must use the other hand to turn the knob so that the threaded bolt contacts the swing arm. The swing arm angular stop position is thus defined by the bolt position, and the swing arm can be swung freely away from the bolt to provide clearance for loading and unloading subsequent wheel assemblies. The swing arm can subsequently be swung back to the same angular stop position defined by the bolt position. When a wheel having different dimensions is loaded on the machine, the angular stop position from the previous wheel must be reset to accommodate the new wheel dimensions. Thus, the user must readjust the bolt position by manually screwing the threaded bolt using the knob. This manual repositioning can involve numerous turns of the threaded bolt and can be time consuming. When repeated several times, the manual repositioning of the threaded bolt can reduce both worker efficiency and machine throughput. Additionally, repeated rotation of the knob by the operator to adjust the threaded bolt location can cause worker hand and arm fatigue and can contribute to worker injury. These problems are amplified when a single machine is used in a multiple-user environment such as a tire changing shop where numerous automobiles are serviced simultaneously.
What is needed, then, is an improved apparatus for adjusting the angular position of a swing arm on a wheel servicing machine. Additional improved methods of using the apparatus are also needed.